Because running commands as root user is a dangerous task and should never be done without care. Especially because it isn’t necessary at all with GVM 10.
The script hasn’t been maintained for several years. It didn’t work for all cases (e.g. redis issues) and therefore gave the users a false impression of having a valid setup. It didn’t give us developers any value and therefore we dropped it.
You have to take a look at the different INSTALL.md files of our components.